I am close to putting the trim back on around the rear of son's 64, not the small window trim, but the larger trim that goes one the rear of the cab. When I removed it, there was black, semi hardened material around the holes that the bolts go through. It has been suggested to use "seam sealer or body caulk", is this readily available at Napa, autozone, etc?? I have some "caulk tape" that is used for motorhome vents, etc, and was curious if that would work. Also, what about something like plumbers putty? Any suggestions are appreciated, I am so tired of leaks and rust I am about to loose my mind. Thanks in advance.